Abstract/Description

In vitro culture media capable of regenerating moderate to high shoots and/or plantlets from meristems
of two yam species – Dioscorea rotundata and Dioscorea alata within comparable duration of 10 weeks
as commonly obtained in other monocots and root and tuber crops were investigated. The study
comprised 125 phytohormone combinations investigated in three factorial experiments each consisting
of an auxin (NAA) and a cytokinin (BAP or kinetin), or two cytokinins only. The frequency of direct
plantlet regeneration, though significantly (P < 0.05) higher for D. alata than for D. rotundata, was low
and ranged from 0 to 10% at 3 weeks after culture (WAC) and 0 to 35% at 8 WAC. At 8 WAC, shoot
regeneration of 42-75% was obtained in D. rotundata in MS medium supplemented with 0.1 M NAA +
0.20 M BAP, and shoot + plantlet regeneration of 60-82% obtained in media containing 0.05 M + 0.20
M BAP or 0.46 M BAP + 0.50 M kinetin in D. alata. Both shoot induction and plantlet regeneration
were species-dependent. Induced shoots were successfully rooted in MS medium within 3 to 4 weeks,
bringing time taken for plantlet regeneration to 11 to 12 weeks. Regenerants were morphologically
similar to the mother plants. Results of the present study will facilitate regeneration of plantlets via
meristem in D. rotundata and D. alata.